Controlling the Size and Dispersion of ZnO@SiO₂ Core-Shell Nanostructure by Addition of Triblock Copolymer Surfactant and pH Adjustment during Precipitation and Encapsulation Process

The potential use of ZnO nanoparticles for cell labeling application has been improved over past several years. Focusing to overcome the tendency of the nanoparticles to aggregation, in this work ZnO nanoparticles have been synthesized by using surfactant-assisted precipitation method. The samples were then characterized by using XRD and UV-Vis Spectroscope. The results showed that the presence of surfactant could help controlling the crystallite size to become smaller (4.02 nm) as compared to the conventional precipitation method (9.45 nm). ZnO nanoparticles that had been coated by the surfactant was then re-coated again by silica shell to form ZnO@SiO2 core-shell. The presence of F-127 coating on the surface of the nanoparticles made the dispersion and the stability of crystallite size better in various encapsulation pH value (4.04 - 4.32 nm). The band gap energy of the ZnO nanoparticles (3.145 - 3.085 eV) also showed a good correlation with the crystallite size (4.02 - 10.38 nm). Therefore, the resulting ZnO@SiO2 core-shell in the present work are potential to be used in cell labeling application.